EIGRP Sim

Refer to the topology.

You have been brought in to troubleshoot an EIGRP network. A network engineer has made configuration changes to the network rendering some locations unreachable. You are to locate the problem and suggest solution to resolve the issue.

Question 1

R5 has become partially isolated from the remainder of the network. R5 can reach devices on directly connected networks but nothing else. What is causing the problem?

A. An outbound distribute list in R3
B. Inbound distribute lists in R5
C. An outbound distribute list in R6
D. Incorrect EIGRP routing process ID in R5

Answer: B

Explanation

R5 is using distribute-lists (with access-list 3) to filter traffic coming from E0/0 & E0/1. Therefore we continue checking access-list 3:

There is no “permit” line in access-list 3 so all traffic is dropped because each access-list always has an implicit “deny all” statement at the end -> R5 cannot learn any routes advertised via EIGRP -> only directly connected will be in the routing table of R5.

Question 2

You have resolved the initial issue between routers R2 and R4, but another issue remains. You are to locate the problem and suggest solution to resolve the issue. The customer has disabled access to the show running-config command.

The network segment between R2 and R4 has become disconnected from the remainder of the network. How should this issue be resolved?

A. Change the autonomous system number in the remainder of the network to be consistent with R2 and R4.
B. Move the 192.168.24.0 network to the EIGRP 1 routing process in R2 and R4.
C. Enable the R2 and R4 router interfaces connected to the 192.168.24.0 network.
D. Remove the distribute-list command from the EIGRP 200 routing process in R2.
E. Remove the distribute-list command from the EIGRP 100 routing process in R2.

Answer: B

Explanation

Check on R2 & R4 with the “show ip eigrp neighbors” command (or maybe the “show ip eigrp interfaces” command also works for this sim):

We see the segments R1 – R2; R4 – R6 are running EIGRP AS 1 while the segment R2 – R4 is running EIGRP AS 100 -> These segments cannot see each other. Therefore we have move the segment R2 – R4 to EIGRP AS 1.